A press is known, for example, from the computer-aided presentation carried out at the WOA conference at Nashville on 7 May 2003, relating to the Sunday 2000-Auto Transfer press (registered trade marks).
The throw-on configuration allows the printing unit to print the web of paper which passes between the blanket cylinders.
A first throw-off configuration is an idle throw-off configuration in which the unit is non-operational.
In a second throw-off configuration, referred to below as the plate-changing throw-off configuration, the blanket cylinder of each printing group is pressed against the plate cylinder of the same group but remains spaced apart from the blanket cylinder of the other printing group.
In addition to the three configurations mentioned above, the Sunday 2000 press also provides a blanket-changing configuration. In this configuration, as in the idle throw-off configuration, the blanket cylinders and plate cylinders are spaced apart from each other.
To this end, starting from the throw-on configuration, the upper plate cylinder has been raised and the lower plate and blanket cylinders have been lowered. The upper blanket cylinder has not been moved.
The idle and plate-changing throw-off configurations, but not the blanket-changing configuration, allow the web of paper to pass between the blanket cylinders of the two printing groups and thus to pass through the printing unit which is not carrying out any printing operation. The web of paper can at the same time continue to be printed by other printing units.
This allows a printing operation to be carried out by some units within the same printing press while the plates of other units are changed to prepare for the following printing operation.
It is thus possible to change printing operation without cutting the web of paper and the losses of paper when a printing operation is changed are limited.
Furthermore, it is possible to prepare a printing operation simultaneously, that is to say, while another printing operation is carried out.
A press of this type, generally referred to as an “Auto Transfer” press (registered trade mark) allows time to be saved with a high level of use and therefore allows costs to be reduced.